Compatibility with Smartphones Min Width: 2.75in/7cmMax Width: 3.5in/8.9cmThe phone ball mount is compatible with most iPhone models, but it doesn't compatible with iPhone 6/6s, iPhone 7/7s, iPhone 8/8s and iPhone SE. ( This ball phone mount is compatible with smartphones above 4.8") LUCKY Car Phone Mount / Fish Finder Holder Mount for Kayak, Small Boat, Float Tube, Canoe, John Boat and etc. The car phone Mount is not only compatible with LUCKY and LUCKYLAKER fish finders, it is also compatible with other brand fish finder displays which is within the arming holder extension range of suction cup mount. It is firm and durable. It enables the fish finder display to be fixed around you and free your hands. You can use the suction cup mount with almost all kinds of kayaks and boats. Durable Performance Saltwater Anti-corrosion Holding Arm like Clamps Features of Base Detachable Suction Cup Tripod Mount BaseThe adapter is a ball with diameter 0.55".The suction cup mount is also compatible with many other devices, like mobile, gps devices and fish finders. 180° + 360° Rotation Design The bracket above the base can be rotated 180°.The ball adapter supports 360° rotation. Three Fixing Ways Suction CupWith ScrewsWith Double Sided Stickers How to Choose the fixing way of GPS Cup Holder Mount / Car Phone Mount? If there is screw holes on your boat or kayak, you can fix the car phone mount by screws.If there is a smooth surface, you can fix the gps holder mount by suction cup.If the surface is not smooth enough, please fix the universial phone mount by double sided stickers.Choose the better fixing way to fix the suction cup to your boat, kayak, truck or anywhere that compatible with one of the three fixing ways.